ASTM E2304-03
(Practice)Standard Practice for Use of a Lif Photo-Fluorescent Film Dosimetry System
Standard Practice for Use of a Lif Photo-Fluorescent Film Dosimetry System
SCOPE
1.1 This practice covers the handling, testing, and procedure for using a lithium fluoride (LiF)-based photo-fluorescent film dosimetry system to measure absorbed dose (relative to water) in materials irradiated by photons or electrons. Other alkali halides that may also exhibit photofluorescence (for example, NaCl, NaF, and KCl) are not covered in this practice. Although various alkali halides have been used for dosimetry for years utilizing thermoluminescence, the use of photoluminescence is relatively new.
1.2 This practice applies to photo-fluorescent film dosimeters (referred hereafter as photo-fluorescent dosimeters) that can be used within part or all of the following ranges:
1.2.1 Absorbed dose range of 5 10-2 to 3 102 kGy (1-3).
1.2.2 Absorbed dose rate range of 0.3 to 2 10 4 Gy/s (2-5)).
1.2.3 Radiation energy range for photons of 0.05 to 10 MeV (2).
1.2.4 Radiation energy range for electrons of 0.1 to 10 MeV (2).
1.2.5 Radiation temperature range of -20 to +60°C (6,7).
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:E2304–03
Standard Practice for
Use of a LiF Photo-Fluorescent Film Dosimetry System
This standard is issued under the fixed designation E2304; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E925 PracticeforMonitoringtheCalibrationofUltraviolet-
Visible Spectrophotometers whose Spectral Bandwidth
1.1 Thispracticecoversthehandling,testing,andprocedure
does not Exceed 2 nm
for using a lithium fluoride (LiF)-based photo-fluorescent film
2.2 ISO/ASTM Standards:
dosimetry system to measure absorbed dose (relative to water)
51204 Practice for Dosimetry in Gamma Irradiation Facili-
in materials irradiated by photons or electrons. Other alkali
ties for Food Processing
halides that may also exhibit photofluorescence (for example,
51261 Guide for Selection and Calibration of Dosimetry
NaCl,NaF,andKCl)arenotcoveredinthispractice.Although
Systems for Radiation Processing
various alkali halides have been used for dosimetry for years
51431 Practice for Dosimetry in Electron and Bremsstrahl-
utilizingthermoluminescence,theuseofphotoluminescenceis
ung Irradiation Facilities for Food Processing
relatively new.
51608 Practice for Dosimetry in an X-ray (Bremsstrahlung)
1.2 This practice applies to photo-fluorescent film dosim-
Facility for Radiation Processing
eters (referred hereafter as photo-fluorescent dosimeters) that
51649 Practice for Dosimetry in an Electron Beam Facility
can be used within part or all of the following ranges:
-2 2
forRadiationProcessingatEnergiesbetween300keVand
1.2.1 Absorbed dose range of 5 3 10 to 3 3 10 kGy
25 MeV
(1-3).
51702 Practice for Dosimetry in a Gamma Irradiation Fa-
1.2.2 Absorbed dose rate range of 0.3 to 2 3 10 Gy/s
cility for Radiation Processing
(2-5)).
51707 Guide for Estimating Uncertainties in Dosimetry for
1.2.3 Radiationenergyrangeforphotonsof0.05to10MeV
Radiation Processing
(2).
51818 Practice for Dosimetry in an Electron Beam Facility
1.2.4 Radiationenergyrangeforelectronsof0.1to10MeV
for Radiation Processing at Energies between 80 keV and
(2).
300 keV
1.2.5 Radiation temperature range of -20 to +60°C (6,7).
51956 Practice for Thermoluminescence-Dosimetry (TLD)
1.3 This standard does not purport to address all of the
Systems for Radiation Processing
safety concerns, if any, associated with its use. It is the
2.3 International Commission on Radiation Units and
responsibility of the user of this standard to establish appro-
Measurements (ICRU) Reports:
priate safety and health practices and determine the applica-
ICRU Report 14 Radiation Dosimetry: X-rays and Gamma
bility of regulatory limitations prior to use.
rays with Maximum Photon Energies Between 0.6 and 50
2. Referenced Documents MeV
ICRU Report 17 Radiation Dosimetry: X-rays Generated at
2.1 ASTM Standards:
Potentials of 5 to 150 kV
E170 TerminologyRelatingtoRadiationMeasurementsand
ICRU Report 34 The Dosimetry of Pulsed Radiation
Dosimetry
ICRUReport35 RadiationDosimetry:ElectronBeamswith
E275 Practice for Describing and Measuring Performance
Energies Between 1 and 50 MeV
of Ultraviolet and Visible Spectrophotometers
ICRU Report 60 Fundamental Quantities and Units for
Ionizing Radiation
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
3. Terminology
Technology and Applications and is the direct responsibility of Subcommittee
E10.01 on Dosimetry for Radiation Processing.
3.1 Definitions:
CurrenteditionapprovedJuly10,2003.PublishedOctober2003.DOI:10.1520/
3.1.1 absorbed dose, D—quantity of ionizing radiation
E2304-03.
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof energy imparted per unit mass of a specified material. The SI
this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from International Commission on Radiation Units and Measure-
the ASTM website. ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, USA.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2304–03
unit of absorbed dose is the gray (Gy), where 1 gray is 3.1.9 electron equilibrium—charged particle equilibrium
equivalent to the absorption of 1 joule per kilogram of the for electrons.
-1
specified material (1 Gy=1 J kg ). The mathematical rela-
3.1.10 fluorescence—one of the four main luminescence
– –
mechanisms. In many materials, it involves the liberated
tionship is the quotient of d´ by dm, where d´ is the mean
electrons falling back to the valence band—directly or via a
incremental energy imparted by ionizing radiation to matter of
relaxationstate—tofillanelectronhole,resultingintherelease
incremental mass dm (see ICRU 60).
ofaphoton.Inthecaseofalkali-halidestheliberatedelectrons
d´
donotfallbacktothevalanceband,butareexcitedtoahigher
D 5
dm
state within the color center, and subsequently fall back to the
3.1.1.1 Discussion—Absorbed dose is sometimes referred
center’s ground state, resulting in the release of a photon.
to simply as dose. For a photon source under conditions of
3.1.11 fluorescence signal, E—the photometric reading by
f
charged particle-equilibrium, the absorbed dose, D, may be
a spectrofluorimeter in terms of light intensity incident on the
expressed as:
photodetector. Typically, the value measured is some quantity
µ
proportional to the standardized quantity, irradiance, E (for
en
i
D5fE
r
example, volts or amperes per unit area of detector surface, V
-2 -2
cm orAcm ).
where:
-2 3.1.12 fluorescence standard—asolidorliquidmaterialthat
f = particle fluence (m ),
produces a fluorescence upon excitation, with an emitted
E = energy of the ionizing radiation (J), and
2 -1
radiance that is calibrated and made traceable to a recognized
µ /r = mass energy absorption coefficient (m kg ).
en
standard.
Ifbremsstrahlungproductionwithinthespecifiedmaterialis
3.1.13 fluorimeter—instrument used to measure the amount
negligible, the mass energy absorption coefficient (µ /r)is
en
of fluorescence signal, E, emitted from a sample upon excita-
equal to the mass energy transfer coefficient (µ /r), and
f
tr
tion by an energy source (usually in the form of light).
absorbeddoseisequaltokermaif,inaddition,charged-particle
equilibrium exists.
3.1.14 irradiance, E—a radiometric term for the radiant
i
-2
3.1.2 alkali halide—a binary compound consisting of a fluxthatisincidentuponasurface,havingunitsofWm .Also
halogen (any of the five elements fluorine, chlorine, bromine,
see radiance.
iodine, and astatine) and an alkali metal (for example, lithium,
NOTE 1—The standard symbol for irradiance is E; however, for this
sodium, and potassium).
documentthesubscript, i,wasaddedtodistinguishirradiancefromenergy
3.1.3 analysis wavelength—wavelength used in a spectro-
of ionizing radiation (see 3.1.1) and fluorescence signal.
photometric instrument to help determine a desired dosimetric
3.1.15 luminescence—photon emission from a solid or liq-
quantity, for example, absorbed dose, by means of the mea-
uid phosphor material during, or after, exposure to a form of
surement of optical absorbance, optical density, reflectance or
energy. The main luminescence mechanisms are fluorescence,
luminescence.
phosphorescence, thermoluminescence, and photolumines-
3.1.4 calibration facility—combinationofanionizingradia-
cence.
tion source and its associated instrumentation that provides a
uniformandreproducibleabsorbeddose,orabsorbed-doserate 3.1.16 measurement quality assurance plan—adocumented
program for the measurement process that ensures on a
traceable to national or international standards at a specified
locationandwithinaspecificmaterial,andthatmaybeusedto continuing basis that the overall uncertainty meets the require-
mentsofthespecificapplication.Thisplanrequirestraceability
derive the dosimetry system’s response function or calibration
curve. to, and consistency with, nationally or internationally recog-
nized standards.
3.1.5 charged-particle equilibrium—the condition that ex-
ists in an incremental volume within a material under irradia- 3.1.17 measurement traceability—theabilitytodemonstrate
tion if the kinetic energies and number of charged particles (of
by means of an unbroken chain of comparisons that a mea-
each type) entering the volume are equal to those leaving the surement is in agreement within acceptable limits of uncer-
volume.
taintywithcomparablenationallyorinternationallyrecognized
3.1.6 color center—imperfections (for example, negative- standards.
or positive-ion vacancies) within the ionic lattice of com-
3.1.18 net fluorescence, DE—measured fluorescence sig-
f
pounds that have trapped electrons or electron holes. These
nal, E, from an irradiated sample, subtracted by the pre-
f
centers, upon excitation by energy in the form of light or heat,
irradiation fluorescence, E , as follows:
o
can produce luminescence.
DE 5 E 2 E
f f o
3.1.7 dosimeter batch—quantity of dosimeters made from a
3.1.19 photo-fluorescent film dosimeter—afilm-typedosim-
specific mass of material with uniform composition, fabricated
eter, which upon excitation by visible or UV light, emits
in a single production run under controlled, consistent condi-
fluorescent light.
tions, and having a unique identification code.
3.1.8 dosimetry system—system used for determining ab- 3.1.20 primary-standard dosimeter—dosimeter of the high-
sorbed dose, consisting of dosimeters, measurement instru- est metrological quality, established and maintained as an
ments and their associated reference standards, and procedures absorbeddosestandardbyanationalorinternationalstandards
for the system’s use. organization.
E2304–03
3.1.21 quality assurance—all systematic actions necessary dose to materials by the photo-stimulated emission of wave-
to provide adequate confidence that a calibration, measure- lengths longer than that of the stimulation wavelength. The
ment, or process is performed to a predefined level of quality.
absorbed dose is obtained from the amount of the light
3.1.22 radiance, L—radiant flux (watts) in a light beam,
emission.Imperfectionswithintheioniclatticeofalkali-halide
emanating from a surface, or falling on a surface, in a given
compounds such as LiF act as traps for electrons and electron
direction, per unit of projected area of the surface (m)as
holes (positively charged negative-ion vacancies). These im-
viewed from that direction, per unit of solid angle (steradians).
perfectionsareknownascolorcentersbecauseofthepartthey
-2 -1
Has units of W m sr . See also, irradiance.
play in the compound’s ability to absorb and then release
3.1.23 reference-standard dosimeter—a dosimeter of high
energyintheformofvisible-lightphotons.Likeanatom,these
metrological quality, used as a standard to provide measure-
color centers have discrete, allowed energy levels, and elec-
ments traceable to, and consistent with, measurements made
trons can be removed from these sites when energy of the
using primary-standard dosimeters.
appropriate wavelength and intensity is transferred to the
3.1.24 stock—part of a dosimeter batch, held by the user.
material. The resulting fluorescence spectra contain discrete
3.1.25 transfer-standard dosimeter—a dosimeter, often a
peaks that can cover a range of wavelengths, depending upon
reference-standard dosimeter suitable for transport between
the type of alkali-halide (8). An example of fluorescence
different locations, used to compare absorbed-dose measure-
spectra from a LiF-based dosimeter is provided in Fig. 1.A
ments.
system of optical filters within a light-detecting instrument
3.1.26 verification—confirmation by examination of objec-
(thatis,fluorimeter)canbeusedtoblockallbutanarrowrange
tive evidence that specified requirements have been met.
of wavelengths that are desired for use.Theories on how color
3.1.26.1 Discussion—In the case of measuring equipment,
centers are formed, how luminescence mechanisms work, and
theresultofverificationleadstoadecisiontorestoretoservice
their application in dosimetry are found in Refs (8-13). For
or to perform adjustments, repair, downgrade, or declare
characterization studies on specific photo-fluorescent dosim-
obsolete. In all cases it is required that a written trace of the
eters see Refs (1-7) and (14-19).
verification performed be kept on the instrument’s individual
4.2 In the application of a specific dosimetry system,
record.
absorbed dose is determined by use of an experimentally-
3.2 Definitions of other terms used in this standard that
derived calibration curve. The calibration curve for the photo-
pertain to radiation measurement and dosimetry may be found
fluorescent dosimeter is the functional relationship between
in Terminology E170. Definitions in Terminology E170 are
DE and D, and is determined by measuring the net fluores-
f
compatible with ICRU 60; that document, therefore, may be
cenceofsetsofdosimetersirradiatedtoknownabsorbeddoses.
used as an alternative reference.
These absorbed doses span the range of utilization of the
4. Significance and Use system.
4.1 A lithium fluoride (LiF)-based photo-fluorescent film 4.3 Photo-fluorescent dosimetry systems require calibration
dosimetry system provides a means of determining absorbed
traceable to national standards. See ISO/ASTM Guide .
NOTE—Also shown are transmission curves for green and red emission filters.
FIG. 1 Excitation Spectrum and Resulting Fluorescence Spectrum from the Sunna LiF-based Film Dosimeter
E2304–03
4.4 The absorbed dose is usually specified relative to water. 6. Performance Check of Instrumentation
Absorbed dose in other materials may be determined by
6.1 At periodic intervals between calibrations, the indi-
applyingtheconversionfactorsdiscussedinISO/ASTMGuide
vidualcomponentinstrumentsofthedosimetrysystem(thatis,
.
fluorimeter and oven, as appropriate) shall have their perfor-
4.5 During calibration and use, possible effects of influence
mance verified. These performance verifications should be
quantities such as temperature, light exposure, post-irradiation
performedatleastmonthlyduringperiodsofuse,andafterany
stabilizationofsignal,andabsorbed-doserateneedtobetaken
maintenance or modification of the instrument that may affect
into account.
its performance. These periodic checks should verify the
4.6 Photo-fluorescent dosimeters are sensitive to light, es-
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.